Primary cutaneous nodular amyloidosis associated with psoriasis

Area of Science:

• Dermatology
• Immunology
• Pathology

Background:

• Primary cutaneous nodular amyloidosis (PCNA) is characterized by firm, waxy nodules, often on extremities.
• Histological features of PCNA can mimic systemic amyloidosis linked to monoclonal immunoglobulin light chains.

Observation:

• A case of PCNA developing within a scar on skin affected by chronic plaque psoriasis is presented.
• This represents the first documented association between PCNA and psoriasis.

Findings:

• The pathogenesis of PCNA may involve T helper (Th)17 cells, which are implicated in both psoriasis and plasma cell dyscrasias.
• The co-occurrence suggests a potential link between psoriasis, Th17 cells, and light chain amyloid deposition in the skin.

Implications:

• This case highlights a potential role for Th17 cells in the development of PCNA, particularly in the context of autoimmune skin diseases.
• Further research into the immunological mechanisms underlying PCNA in psoriatic lesions is warranted.